Consoldated Network Storage?

bigstupid asks: "Is there anyway to better utilize storage space on your network? I have a home network with about nine permanently attached PCs. A few of these are older PII300 with smaller hard drives (3-10GB). What I want to do is consolidate as much of the network storage as possible. That is: Instead of 2.4GB here, 4.6GB there, 5GB hither, 5BG tither, and 6 GB yon, I would like this storage space to appear to any computer I designate a 'client' to see and use this storage space as one large (in the case above 23GB) volume. I know I can do this within a machine with logical volumes or RAID, but is there a piece of software - client or server side - that will do this on Linux or Windows?"